University:
West Coast University
Course:
PHAR 840 | Immunologic Conditions and Special Populations
Academic year:

2025
Views:

157

Pages:

10
Author:

Aparna Rao C

HUMORAL IMMUNITY COMPLEMENT SYSTEM AND ANTIBODIES • Lohit krishna • Roll no:- 14 • Antigen recognition by B lymphocytes. 1 • Activation of B cells with help from T-helper (Th2) cells. 2 Steps of Humoral Immunity • Clonal proliferation of activated B cells. 3 4 • Secretion of specific antibodies to target the antigen. • Differentiation into plasma cells and memory B cells. Activation of B Cells • B cells recognize antigens through membrane-bound antibodies (B-cell receptors). • Binding of antigen and cytokine signals from Th2 cells activate the B cell. • Activated B cells undergo clonal expansion and affinity maturation. Differentiation & Antibody Production • Activated B cells differentiate into: • Plasma cells → produce and secrete antibodies. • Memory B cells → remain for faster future response. • Antibodies bind to antigens and mark them for destruction. Types of Humoral Immune Responses COMPLEMENT SYSTEM • The complement system includes three pathways:• Classical pathway • Alternate pathway • Lectin pathway TERMINAL PATHWAY FUNCTIONS OF COMPLEMENT PATHWAY Phagocytosis(C3a,C4 a,C5a):- Promote phagocytosis. Opsonization(C3b):Marks the pathogen for phagocytosis. Cytolysis:(C5b,C6,C7, C8,C9):- causes cytolysis of the microbes Antibody-Mediated Response • Antibodies bind specifically to antigens on pathogens. • They neutralize, opsonize, or activate complement system. • Helps eliminate extracellular microbes and toxins. • Provides basis for vaccine-induced immunity.